In the manufacture of gas-fueled devices such as incinerators, for example, it is often highly desirable that the burner thereof be located in a chamber remote from the chamber in which combustion takes place. This thus requires that the burner be designed so as to efficiently produce an exceptionally long flame which will extend into the remote combustion area.
Burner structures have been made which employ an outer tubular casing which encloses a parallel short tubular flame holder, with air being introduced simultaneously into adjacent ends of the casing and flame holder. Gas is introduced into the flame holder for mixing with the air therein for primary combustion when ignited adjacent the exit end of the flame holder. Secondary combustion is sustained by the air flowing between the flame holder and casing.
In many such apparatus, space restrictions are such as to require that incoming air flow be redirected along a path which is substantially perpendicular to its initial direction.
Copending U.S. patent application Ser. No. 466,096, now U.S. Pat. No. 3,915,625 filed May 2, 1974 is an example of such a known burner structure.
However, in known burners of this character it has been found difficult to regulate or adjust the quantity and velocity of primary air within the flame holder for most efficient ignition. More particularly it has been found difficult to insure repetitive ignitions such as are required for certification by the American Gas Association. In a device such as disclosed in the aforementioned copending application Ser. No. 466,096 now U.S. Pat. No. 3,915,625, the production of uniform velocity air flow on both sides of the flame holder within the casing has been sufficient for certain selected uses. However, in some cases it has been found that while initial ignition is readily achieved, repetitive and relatively closely spaced subsequent ignitions will not always satisfactorily occur.